William's aunt, Sarah Ferguson, who is not invited to the April 29 wedding, famously wore a garland of flowers into Westminster Abbey on her wedding day. Her headwear symbolized a commoner's entering the ceremony.

After the vows, the flowers came off to reveal a new tiara commissioned by Garrard Jewelers, highlighting a new Ferguson, Duchess of York.

Heirloom Might Be in Store for Middleton

Some experts suggest that the queen will give Middleton an heirloom tiara to wear on her big day.

"Given the multitude of Garrard tiaras that are in the royal family possession, it is likely there will be one that has carried on down the generations that she would wear," Eric Deardorff, CEO of official royal jewelers Garrard, told ABC News.

Garrard is the world's oldest jeweler. It produced Diana's ring and some of the queen's tiaras.